TY - JOUR
T1 - Nuclear factor κb mediates the inhibitory effects of interleukin-1 on growth hormone-inducible gene expression
AU - Buzzelli, Mark D.
AU - Navaratnarajah, Maithili
AU - Ahmed, Tamer
AU - Nagarajan, Murali
AU - Shumate, Margaret L.
AU - Lang, Charles H.
AU - Cooney, Robert N.
PY - 2008/6
Y1 - 2008/6
N2 - Background: Hepatic expression of growth hormone (GH)-inducible genes serine protease inhibitor (Spi 2.1) and insulin-like growth factor (IGF)-I are inhibited by interleukin (IL)-1. The current study examines the role of the nuclear factor κB (NFκB) pathway and suppressor of cytokine signaling (SOCS)-3 expression as potential mechanisms for IL-1-mediated GH resistance. Methods: CWSV-1 hepatocytes were cotransfected with Spi 2.1 or IGF-1 promoter luciferase constructs and empty pCMV4 vector or dominant negative inhibitor-κBα (IκBα)S/A construct. Cells were treated with or without IL-1 and then stimulated with or without recombinant human GH. Cell extracts were assayed for luciferase activity and protein, normalized and expressed as fold-induction. CWSV-1 cells transfected with pCMV4 or IκBαS/A were treated with or without IL-1 then SOCS-3 mRNA was measured. Finally, CWSV-1 cells were cotransfected with a SOCS-3 promoter construct with or without pCMV4 or IκBαS/A and then stimulated with or without IL-1 to investigate SOCS-3 promoter activity. Results: CWSV-1 cells cotransfected with pCMV4 demonstrated a three- to fivefold induction of Spi 2.1 or IGF-1 promoter activity after GH stimulation that was almost completely inhibited by IL-1. Cotransfection with IκBαS/A increased GH-inducible Spi 2.1 and IGF-1 promoter activity, but the inhibitory effects of IL-1 on both promoters were attenuated by cotransfection with IκBαS/A. IL-1 stimulated SOCS-3 mRNA expression and promoter activity. Cotransfection with IκBαS/A increased IL-1-inducible SOCS-3 promoter activity, but not SOCS-3 mRNA or protein. Conclusions: Signaling via the NFκB pathway is responsible for the inhibitory effects of IL-1 on GH-inducible gene expression by a mechanism that does not seem to involve increased SOCS-3 expression.
AB - Background: Hepatic expression of growth hormone (GH)-inducible genes serine protease inhibitor (Spi 2.1) and insulin-like growth factor (IGF)-I are inhibited by interleukin (IL)-1. The current study examines the role of the nuclear factor κB (NFκB) pathway and suppressor of cytokine signaling (SOCS)-3 expression as potential mechanisms for IL-1-mediated GH resistance. Methods: CWSV-1 hepatocytes were cotransfected with Spi 2.1 or IGF-1 promoter luciferase constructs and empty pCMV4 vector or dominant negative inhibitor-κBα (IκBα)S/A construct. Cells were treated with or without IL-1 and then stimulated with or without recombinant human GH. Cell extracts were assayed for luciferase activity and protein, normalized and expressed as fold-induction. CWSV-1 cells transfected with pCMV4 or IκBαS/A were treated with or without IL-1 then SOCS-3 mRNA was measured. Finally, CWSV-1 cells were cotransfected with a SOCS-3 promoter construct with or without pCMV4 or IκBαS/A and then stimulated with or without IL-1 to investigate SOCS-3 promoter activity. Results: CWSV-1 cells cotransfected with pCMV4 demonstrated a three- to fivefold induction of Spi 2.1 or IGF-1 promoter activity after GH stimulation that was almost completely inhibited by IL-1. Cotransfection with IκBαS/A increased GH-inducible Spi 2.1 and IGF-1 promoter activity, but the inhibitory effects of IL-1 on both promoters were attenuated by cotransfection with IκBαS/A. IL-1 stimulated SOCS-3 mRNA expression and promoter activity. Cotransfection with IκBαS/A increased IL-1-inducible SOCS-3 promoter activity, but not SOCS-3 mRNA or protein. Conclusions: Signaling via the NFκB pathway is responsible for the inhibitory effects of IL-1 on GH-inducible gene expression by a mechanism that does not seem to involve increased SOCS-3 expression.
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U2 - 10.1097/TA.0b013e318174e8a4
DO - 10.1097/TA.0b013e318174e8a4
M3 - Article
C2 - 18545105
AN - SCOPUS:67650302023
SN - 0022-5282
VL - 64
SP - 1427
EP - 1435
JO - Journal of Trauma - Injury, Infection and Critical Care
JF - Journal of Trauma - Injury, Infection and Critical Care
IS - 6
ER -